35 results on '"Lyle S"'
Search Results
2. Endometrial Culture and Antimicrobial Therapy
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LYLE, S, primary
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- 2003
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3. Biobehavioral Antecedents in the Development of Infant–Mother Attachment∗∗The preparation of this chapter was supported in part by grant #301-443-4843 from the National Institute of Mental Health to Peter Barglow and by a Foundation for Child Development Research Program grant for Young Scholars in Social and Affective Development to Lyle S. Joffe. The authors gratefully acknowledge the assistance of Nancy Hill, Carolyn Zoellner, and Carol Israel in the collection, coding, and analysis of the data presented.
- Author
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JOFFE, LYLE S., primary, VAUGHN, BRIAN E., additional, BARGLOW, PETER, additional, and BENVENISTE, ROBERT, additional
- Published
- 1985
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4. Biobehavioral Antecedents in the Development of Infant–Mother Attachment∗∗The preparation of this chapter was supported in part by grant #301-443-4843 from the National Institute of Mental Health to Peter Barglow and by a Foundation for Child Development Research Program grant for Young Scholars in Social and Affective Development to Lyle S. Joffe. The authors gratefully acknowledge the assistance of Nancy Hill, Carolyn Zoellner, and Carol Israel in the collection, coding, and analysis of the data presented
- Author
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Robert Benveniste, Lyle S. Joffe, Brian E. Vaughn, and Peter Barglow
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Psychology ,Developmental psychology - Published
- 1985
5. A structuration theory guided analysis of the hospitalization experience for people living with HIV who use drugs: My rules and their rules.
- Author
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O'Leary W, Brennan DJ, Ashcroft R, Carusone SC, Guta A, and Strike C
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- Delivery of Health Care, Health Personnel, Hospitalization, Hospitals, Humans, Qualitative Research, HIV Infections drug therapy
- Abstract
Background: People living with HIV (PLWH) who use drugs in harmful amounts, types and/or modes of consumption (e.g., drugs from unregulated sources) experience barriers to accessing conventional healthcare services. The overall experience of PLWH who use drugs while admitted to hospital directly influences their treatment engagement. Members of interdisciplinary care teams within hospitals can shape the experiences of PLWH who use drugs by virtue of direct practice. However, little discussion in the research literature articulates the self-reported experiences of PLWH who use drugs specific to their time spent in hospital METHODS: Semi-structured interviews were conducted with participants who: i) self-reported HIV ii) had a hospital admission in the past year; and iii) used drugs at time of admission. A structuration theory-guided thematic analysis was used to understand the beliefs and practices identified by participants that affect their hospital admission experience RESULTS: Participants (n = 22) identified two sets of rules that influence their hospital admission; personal rules, used for navigating the admission, and hospital rules (i.e., "their rules"). Participants indicated that healthcare providers' use of a constructed difficult patient identity shaped their experiences while admitted as hospital in-patients CONCLUSION: Healthcare equity is not possible when all people are treated the same; social practices occurring during a hospital admission privilege some (e.g., healthcare providers) and not others (e.g., PLWH who use drugs) and will continue to dictate the hospital admission experience of PLWH who use drugs. Hospitalized PLWH who use drugs can change their actions, ergo altering social practices between themselves and health care providers leading to a positive effect on the overall hospital admission experience. However, barriers experienced by PLWH who use drugs limit the degree to which they can implement effective positive change., Competing Interests: Declarations of Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)
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- 2022
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6. Stallion Sperm Integrity After Centrifugation to Reduce Seminal Plasma Concentration and Cool Storage for 4 days.
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Len J, Beehan D, Eilts B, Ebrahimie E, and Lyle S
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- Animals, Centrifugation veterinary, Horses, Male, Sperm Motility, Spermatozoa, Semen, Semen Analysis veterinary
- Abstract
The objective of the study was to investigate if reducing the seminal plasma of stallion extended semen by centrifugation once will suffice to maintain acceptable semen quality for insemination after 4 days of cool storage. Collected semen was extended to 25 × 10
6 sperm/mL and subjected to one of the following treatments: noncentrifuged (control), centrifuged for 10 minutes at 900 × g and 1800 × g. The supernatant was partially removed, and the sperm pellet, reconstituted and re-extended. It was then placed in a passive cooling device overnight and then transferred to a refrigerator for the remainder of the cooling period. At day 0, 2, and 4, total motility (TM), progressive motility (PM), and plasma (PLM) and acrosomal membrane integrity were assessed. Centrifuged groups had higher TM and PM at day 4 than the control group (P < .05). Likewise, centrifuged groups had higher intact PLM in day 4 (P < .05). A single centrifugation cycle to reduce seminal plasma concentration will suffice to preserve sperm integrity acceptable for an artificial insemination dose up to 4 days of cool storage., (Copyright © 2019 Elsevier Inc. All rights reserved.)- Published
- 2020
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7. Cushioned versus noncushioned centrifugation: sperm recovery rate and integrity.
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Len JA, Beehan DP, Lyle SK, and Eilts BE
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- Acrosome physiology, Animals, Cell Membrane physiology, Cell Separation methods, Cell Separation statistics & numerical data, Cell Separation veterinary, Centrifugation methods, Centrifugation veterinary, Horses, Male, Semen Analysis statistics & numerical data, Semen Analysis veterinary, Sperm Count statistics & numerical data, Semen cytology, Semen Analysis methods
- Abstract
It was hypothesized that optimal sperm recovery rate (RR) without damage to the sperm would be obtained after centrifugation without a cushion solution. Semen collected three times from six light breed stallions was extended to 25 × 10(6) sperm/mL and centrifuged at CON (noncentrifuged), 900NC (no-cushion), 900C (cushion), 1800NC, and 1800C × g for 10 minutes. Sperm concentration, motility (TM and PM), and intact plasma membranes (PLM) and acrosomes (ACR) pre- and postcentrifugation (D0) and after 24 hours (D1) of cooling were evaluated. The RR in the CON (100 ± 0.0), 900NC (93.7 ± 2.9), and 1800NC (96.7 ± 2.6) groups was significantly higher than the 900C (68.7 ± 4.6) and 1800C (79.6 ± 3.5) groups. The D0 TM and PM were not different between the CON, 900NC, 900C, and 1800C, but were lower for the 1800NC group. The D1 TM and PM of the 900NC (75.2 ± 3.8 and 71.1 ± 4.1) and 900C (76.2 ± 3.7 and 72.4 ± 4.0) groups were significantly higher than the 1800NC (71.7 ± 4.1 and 67.3 ± 4.4) and 1800C (71.6 ± 4.1 and 67.2 ± 4.4) groups, and the CON (66.2 ± 4.5 and 60.0 ± 4.8) group was significantly lower than the other groups. The D1 PLM of the CON, 900NC, 900C, 1800NC, and 1800C groups were not different. The ACR on D1 was significantly lower for the CON (93.0 ± 2.4) group compared with all other groups. Optimal RR preserving sperm integrity was obtained in the 900NC group., (Copyright © 2013 Elsevier Inc. All rights reserved.)
- Published
- 2013
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8. Factors affecting sperm recovery rates and survival after centrifugation of equine semen.
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Ferrer MS, Lyle SK, Eilts BE, Eljarrah AH, and Paccamonti DL
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- Animals, Cell Survival, Centrifugation adverse effects, Centrifugation methods, Cryoprotective Agents, Male, Semen physiology, Semen Preservation methods, Sperm Count, Sperm Motility, Centrifugation veterinary, Horses, Semen cytology, Semen Preservation veterinary, Spermatozoa physiology
- Abstract
Conventional centrifugation protocols result in important sperm losses during removal of the supernatant. In this study, the effect of centrifugation force (400 or 900 × g), duration (5 or 10 min), and column height (20 or 40 mL; Experiment 1); sperm concentration (25, 50, and 100 × 10(6)/mL; Experiment 2), and centrifugation medium (EZ-Mixin CST [Animal Reproduction Systems, Chino, CA, USA], INRA96 [IMV Technologies, Maple Grove, MN, USA], or VMDZ [Partnar Animal Health, Port Huron, MI, USA]; Experiment 3) on sperm recovery and survival after centrifugation and cooling and storage were evaluated. Overall, sperm survival was not affected by the combination of centrifugation protocol and cooling. Total sperm yield was highest after centrifugation for 10 min at 400 × g in 20-mL columns (95.6 ± 5%, mean ± SD) or 900 × g in 20-mL (99.2 ± 0.8%) or 40-mL (91.4 ± 4.5%) columns, and at 900 × g for 5 min in 20-mL columns (93.8 ± 8.9%; P < 0.0001). Total (TMY) and progressively motile sperm yield followed a similar pattern (P < 0.0001). Sperm yields were not significantly different among samples centrifuged at various sperm concentrations. However, centrifugation at 100 × 10(6)/mL resulted in significantly lower total sperm yield (83.8 ± 10.7%) and TMY (81.7 ± 6.8%) compared with noncentrifuged semen. Centrifugation in VMDZ resulted in significantly lower TMY (69.3 ± 22.6%), progressively motile sperm yield (63.5 ± 18.2%), viable yield (60.9 ± 36.5%), and survival of progressively motile sperm after cooling (21 ± 10.8%) compared with noncentrifuged semen. In conclusion, centrifuging volumes of ≤ 20 mL minimized sperm losses with conventional protocols. With 40-mL columns, it may be recommended to increase the centrifugal force to 900 × g for 10 min and dilute the semen to a sperm concentration of 25 to 50 × 10(6)/mL in a milk- or fractionated milk-based medium. The semen extender VMDZ did not seem well suited for centrifugation of equine semen., (Copyright © 2012 Elsevier Inc. All rights reserved.)
- Published
- 2012
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9. Mdm2-p53 signaling regulates epidermal stem cell senescence and premature aging phenotypes in mouse skin.
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Gannon HS, Donehower LA, Lyle S, and Jones SN
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- Animals, Cyclin-Dependent Kinase Inhibitor p16 analysis, Mice, Phenotype, Cellular Senescence, Epidermal Cells, Proto-Oncogene Proteins c-mdm2 physiology, Signal Transduction physiology, Skin Aging, Stem Cells physiology, Tumor Suppressor Protein p53 physiology
- Abstract
The p53 transcription factor is activated by various types of cell stress or DNA damage and induces the expression of genes that control cell growth and inhibit tumor formation. Analysis of mice that express mutant forms of p53 suggest that inappropriate p53 activation can alter tissue homeostasis and life span, connecting p53 tumor suppressor functions with accelerated aging. However, other mouse models that display increased levels of wildtype p53 in various tissues fail to corroborate a link between p53 and aging phenotypes, possibly due to the retention of signaling pathways that negatively regulate p53 activity in these models. In this present study, we have generated mice lacking Mdm2 in the epidermis. Deletion of Mdm2, the chief negative regulator of p53, induced an aging phenotype in the skin of mice, including thinning of the epidermis, reduced wound healing, and a progressive loss of fur. These phenotypes arise due to an induction of p53-mediated senescence in epidermal stem cells and a gradual loss of epidermal stem cell function. These results reveal that activation of endogenous p53 by ablation of Mdm2 can induce accelerated aging phenotypes in mice., (Copyright © 2011 Elsevier Inc. All rights reserved.)
- Published
- 2011
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10. Immediate and delayed (after cooling) effects of centrifugation on equine sperm.
- Author
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Len JA, Jenkins JA, Eilts BE, Paccamonti DL, Lyle SK, and Hosgood G
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- Animals, Male, Sperm Motility, Tissue and Organ Harvesting veterinary, Centrifugation veterinary, Horses, Spermatozoa physiology
- Abstract
The objectives of this study were to determine the effects of centrifugation on equine sperm total and progressive motility, viability, and acrosomal integrity. We hypothesized that although high centrifugation forces would be detrimental to equine Equus caballus sperm, recovery rates would increase. Ejaculates from six stallions were collected, extended to a concentration of 25x10(6) cells/mL, and subjected for 10min to (1) no centrifugation (NC) or (2) centrifugation at 400xg, (3) 900xg, or (4) 4500xg. Before and after centrifugation (Day 0), and after 24h of cooling (Day 1), sperm motility was assessed by computer-assisted semen analysis, and samples were stained with SYBR-14/propidium iodide (PI) for viability and with PI/fluorescein isothiocyanate (FITC)-Peanut aglutinin (PNA) (Arachis hypogaea) for acrosomal integrity. The effect of treatment and day on motility, viability, and acrosomal integrity was determined using a mixed linear model. Compared with the other treatments, centrifugation at 4500xg reduced all end points measured (P<0.05). Both 400xg and 900xg yielded lower recovery rates than that of 4500xg (NC=100.0+/-0.0%; 400xg=54.4+/-8.6%; 900xg=75.0+/-7.1%; 4500xg=97.9+/-2.8%; P<0.05). Centrifugation at 400xg or 900xg did not damage equine sperm. Based on these findings, further studies of centrifugal forces between 900xg and 4500xg are warranted to determine the optimal force that maximizes recovery rate, minimizes sperm damage, and does not affect fertility.
- Published
- 2010
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11. Disorders of sexual development in the dog and cat.
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Lyle SK
- Subjects
- Animals, Cats, Disorders of Sex Development diagnosis, Dogs, Female, Gonadal Dysgenesis diagnosis, Gonadal Dysgenesis veterinary, Male, Sex Chromosome Disorders diagnosis, Sexual Development, Cat Diseases diagnosis, Disorders of Sex Development veterinary, Dog Diseases diagnosis, Sex Chromosome Disorders veterinary
- Abstract
Normal sexual differentiation occurs in three sequential steps--establishment of chromosomal (genetic) sex, development of gonadal sex, and development of phenotypic sex. Errors in the establishment of chromosomal, gonadal, or phenotypic sex cause abnormal sexual differentiation. Affected individuals are identified with a wide variety of patterns from ambiguous genitalia, to apparently normal genitalia with sterility or infertility. When a patient is suspected of having a disorder of sexual development, analysis of the chromosomal constitution and complete gross and histopathologic description of the gonads, internal and external genitalia are required to correctly categorize the type of disorder.
- Published
- 2007
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12. In vitro differences between keratinocyte stem cells and transit-amplifying cells of the human hair follicle.
- Author
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Roh C, Tao Q, Photopoulos C, and Lyle S
- Subjects
- Cell Cycle physiology, Cell Movement, Cells, Cultured, Hair Follicle physiology, Humans, Keratinocytes physiology, Stem Cells physiology, Hair Follicle cytology, Keratinocytes cytology, Stem Cells cytology
- Abstract
Epithelial stem cells within the human hair follicle are critical for hair development, hair cycling, wound healing, and tumorigenesis. We and others have previously shown that the hair follicle bulge area contains keratinocyte stem cells, whereas the hair matrix represents the proliferating and differentiating transit-amplifying (TA) cell compartment. In order to better characterize the phenotypic differences between human keratinocyte stem cells and their daughter TA cells, we compared the in vitro properties of cell adhesion, cell migration, clonogenicity, and in vitro life span. Epithelial outgrowths from the hair matrix appeared within 2 d of explant, whereas stem cell outgrowths appeared between 7 and 10 d after explant. Both populations form colonies; however, stem cells from telogen follicles formed more total colonies, and more colonies greater than 3 mm. Upon subculture, stem cells formed colonies until passage 6 and terminally differentiated at passage 7, whereas TA cells only formed colonies until passage 2. Stem cells express more beta1 integrin and adhere more rapidly to collagen IV. Most strikingly, TA cells showed a 7-fold greater mobility on migration assays than stem cells (0.704 vs 0.102 microm per min). These results help define the human hair follicle stem cell and TA cell phenotypes and correlate with the in vivo properties of these compartments.
- Published
- 2005
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13. Low-dose insemination--why, when and how.
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Lyle SK and Ferrer MS
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- Animals, Cryopreservation methods, Cryopreservation veterinary, Endometritis etiology, Endometritis veterinary, Female, Horse Diseases etiology, Hysteroscopy adverse effects, Hysteroscopy veterinary, Insemination, Artificial adverse effects, Insemination, Artificial methods, Male, Pregnancy, Semen Preservation methods, Semen Preservation veterinary, Sperm Count, Sperm Motility, Time Factors, Horses, Insemination, Artificial veterinary
- Abstract
The typical dose for insemination into the uterine body of the mare is > 300 x 10(6) progressively motile spermatozoa (PMS) and an insemination dose of > 200 x 10(6) PMS is recommended for frozen-thawed semen. Low-dose insemination techniques allow for a drastic reduction in the numbers of spermatozoa required to achieve pregnancy. Acceptable pregnancy rates can be achieved with doses ranging from 1 to 25 x 10(6) PMS in volumes ranging from 20 to 1000 microL. Two techniques have been described: hysteroscopic insemination and transrectally guided deep horn insemination using a pipette. Similar pregnancy rates can be attained by either method when 5 x 10(6) PMS are used. Hysteroscopic insemination may provide an advantage when the dose is 1-3 x 10(6) PMS. These techniques have the potential to make more efficient use of frozen-thawed or sex-sorted semen from certain stallions. The use of low-dose insemination to improve fertility of infertile stallions warrants further investigation.
- Published
- 2005
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14. Autofluorescence in the stem cell region of the hair follicle bulge.
- Author
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Wun BP, Tao Q, and Lyle S
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- Fluorescence, Humans, Microscopy, Fluorescence, Hair Follicle cytology, Keratinocytes cytology, Stem Cells cytology
- Published
- 2005
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15. Keratin 15 promoter targets putative epithelial stem cells in the hair follicle bulge.
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Liu Y, Lyle S, Yang Z, and Cotsarelis G
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- Animals, Cell Differentiation, Cell Division, Humans, Keratin-15, Mice, Mice, Inbred C57BL, Mice, Transgenic, Skin Neoplasms etiology, Wound Healing, Epithelial Cells cytology, Hair Follicle cytology, Keratins genetics, Promoter Regions, Genetic, Stem Cells physiology
- Abstract
Putative epithelial stem cells in the hair follicle bulge are thought to play pivotal roles in the homeostasis, aging, and carcinogenesis of the cutaneous epithelium. Elucidating the role of bulge cells in these processes has been hampered by the lack of gene promoters that target this area with specificity. Here we describe the isolation of the mouse keratin 15 (K15) promoter and demonstrate its utility for preferentially targeting hair follicle bulge cells in adult K15/lacZ transgenic mice. We found that patterns of K15 expression and promoter activity changed with age and correlated with levels of differentiation within the cutaneous epithelium; less differentiated keratinocytes in the epidermis of the neonatal mouse and in the bulge area of the adult mouse preferentially expressed K15. These findings demonstrate the utility of the K15 promoter for targeting epithelial stem cells in the hair follicle bulge and set the stage for elucidating the role of bulge cells in skin biology.
- Published
- 2003
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16. Differential expression of cyclin D1 in the human hair follicle.
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Xu X, Lyle S, Liu Y, Solky B, and Cotsarelis G
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- Computer Systems, Cyclin D1 genetics, Cyclin D2, Cyclin D3, Cyclins metabolism, Dissection, Gene Expression, Hair Diseases metabolism, Humans, Oligonucleotide Array Sequence Analysis, Pilomatrixoma metabolism, Polymerase Chain Reaction, Skin Neoplasms metabolism, Tissue Distribution, Cyclin D1 metabolism, Hair Follicle metabolism
- Abstract
The proliferation of keratinocytes in the hair follicle varies from slowly cycling, intermittently proliferating stem cells in the bulge to rapidly proliferating, transient cells in the bulb. To better understand the biological differences between these two compartments, we sought to identify differentially expressed genes using cDNA macroarray analysis. Cyclin D1 was one of 13 genes increased in the bulge compared to the bulb, and its differential expression was corroborated by quantitative real-time polymerase chain reaction (PCR) on the original samples. Using immunohistochemical staining, laser-capture microdissection (LCM) and quantitative real-time PCR, we localized cyclin D1 to the suprabasal cells of the telogen bulge and anagen outer root sheath (ORS). Surprisingly, cyclin D1, D2, and D3 were not detectable by immunohistochemistry in the rapidly proliferating hair-producing cells of the anagen bulb (matrix cells), while these cells were strongly positive for Ki-67 and retinoblastoma protein. In contrast, pilomatricoma, a tumor thought to be derived from matrix cells, was positive for cyclin D1, D2, and D3. Our results suggest that cyclin D1 may mediate the proliferation of stem cells in the bulge to more differentiated transient amplifying cells in the suprabasal ORS. In contrast, non-cyclin D1-proteins appear to control cell division of the highly proliferative bulb matrix cells. This non-cyclin D1-mediated proliferation may provide a protective mechanism against tumorigenesis, which is overridden in pilomatricomas. Our data also demonstrate that the combination of DNA macroarray, LCM and quantitative real-time PCR is a powerful approach for the study of gene expression in defined cell populations with limited starting material.
- Published
- 2003
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17. Cancer pain and psychosocial factors: a critical review of the literature.
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Zaza C and Baine N
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- Humans, Psychology, Neoplasms complications, Neoplasms psychology, Pain etiology, Pain psychology
- Abstract
Poor pain assessment is cited as one barrier to the adequate treatment of cancer pain. The identification of relevant psychosocial factors may improve the assessment of chronic cancer pain. This article presents: 1) a critical review of the evidence for an association between chronic cancer pain and psychological distress, social support, and coping; 2) clinical implications of the findings; and 3) recommendations for future research. Fourteen of the 19 reviewed studies on psychological distress found a significant association between increased pain and increased distress. Seven of the eight studies on social support found significant association between higher levels of pain and decreased levels of social activities and social support. Three of the four studies that examined coping strategies found that increased catastrophizing was significantly associated with more intense pain. Based on several criteria, the evidence is considered Strong for psychological distress, Moderate for social support, and Inconclusive for coping. This review suggests that comprehensive chronic pain assessment should include routine screening for psychological distress.
- Published
- 2002
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18. Atrichia caused by mutations in the vitamin D receptor gene is a phenocopy of generalized atrichia caused by mutations in the hairless gene.
- Author
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Miller J, Djabali K, Chen T, Liu Y, Ioffreda M, Lyle S, Christiano AM, Holick M, and Cotsarelis G
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- Alopecia etiology, Female, Humans, Middle Aged, Mutation, Proteins genetics, Transcription Factors, Alopecia genetics, Receptors, Calcitriol genetics
- Abstract
Generalized atrichia with papules is a rare disorder characterized by loss of hair shortly after birth and development of cutaneous cysts. Mutations in the hairless gene (HR) cause this phenotype in both mouse and human. Here we present a case of atrichia with papules in a patient with a normal HAIRLESS gene but with mutations in both alleles of the VITAMIN D RECEPTOR. The patient exhibited vitamin D resistant rickets, which was confirmed by an absent response of her fibroblasts to 1,25-dihydroxyvitamin D3 in vitro. Similar to individuals with HAIRLESS mutations, her skin showed an absence of normal hair follicles and the presence of follicular remnants and cysts. The cyst epithelium contained keratin-15- and keratin-17-positive cells suggesting derivation from the hair follicle bulge and the presence of epithelial stem cells. Although hair loss has been reported in association with hereditary vitamin D resistant rickets, we now characterize this alopecia as clinically and pathologically indistinguishable from generalized atrichia with papules, which was previously thought to be caused only by mutations in HAIRLESS. These findings suggest that VDR and HR, which are both zinc finger proteins, may be in the same genetic pathway that controls postnatal cycling of the hair follicle.
- Published
- 2001
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19. Human hair follicle bulge cells are biochemically distinct and possess an epithelial stem cell phenotype.
- Author
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Lyle S, Christofidou-Solomidou M, Liu Y, Elder DE, Albelda S, and Cotsarelis G
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- Antibodies, Monoclonal, Antibody Specificity, CD8 Antigens immunology, Cell Differentiation, Epithelial Cells cytology, Epithelial Cells physiology, Hair Follicle cytology, Humans, Immunohistochemistry, Integrin beta1 immunology, Keratins immunology, Stem Cells cytology, Stem Cells physiology, CD8 Antigens metabolism, Hair Follicle physiology, Integrin beta1 metabolism, Keratins metabolism
- Abstract
Stem cells are vital for the homeostasis of self-renewing tissues and their manipulation may have wide ranging applications, including gene therapy, wound repair, and tissue transplantation. Although rodent hair follicle stem cells have been localized to the follicle bulge, the location of human hair follicle stem cells is less clear, and their characterization has been hampered by a lack of cellular markers for the bulge area. We demonstrate that the C8/144B monoclonal antibody, originally raised against a CD8 peptide sequence, immunostains the human hair follicle bulge. We show that this antibody recognizes cytokeratin 15 (K15) in keratinocytes, and that K15-positive bulge cells possess a stem cell phenotype characterized by their slowly cycling nature, proliferation at the onset of new hair follicle growth, and high level of beta1 integrin expression. These results localize human hair follicle stem cells to the bulge and suggest that K15 is preferentially expressed in epithelial stem cells.
- Published
- 1999
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20. Sulfate activation and transport in mammals: system components and mechanisms.
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Schwartz NB, Lyle S, Ozeran JD, Li H, Deyrup A, Ng K, and Westley J
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- Animals, Antiporters metabolism, Biological Transport, Mice, Phosphoadenosine Phosphosulfate metabolism, Phosphotransferases (Alcohol Group Acceptor) metabolism, Rats, Sulfate Adenylyltransferase metabolism, Sulfates metabolism
- Abstract
Extensive studies on the mammalian sulfate-activating enzymes and PAPS translocase have enhanced our understanding of the overall pathway of sulfate activation and utilization. Isolation of the PAPS-synthesizing activities from rat chondrosarcoma and preparation of stable non-hydrolyzable analogs of APS and PAPS have facilitated the kinetic characterization of mammalian ATP sulfurylase and APS kinase. These studies provided the basis for further experimental work showing that APS, the labile intermediate product, is channeled directly between the sulfurylase and kinase active sites. The defect in the brachymorphic mutant mouse lies in this channeling mechanism, thus interfering with efficient PAPS production. The rat chondrosarcoma ATP sulfurylase and APS kinase activities, in fact, reside in a single bifunctional cytoplasmic protein, which has now been cloned and expressed. The mechanism by which PAPS reaches its sites of utilization in the Golgi lumen has also been elucidated: The PAPS translocase is a 230-kDa integral Golgi membrane protein which functions as an antiport.
- Published
- 1998
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21. Synthesis and utilization of a nonhydrolyzable phosphoadenosine phosphosulfate analog.
- Author
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Ng K, D'Souza M, Callahan L, Geller DH, Kearns AE, Lyle S, and Schwartz NB
- Subjects
- Animals, Chromatography, High Pressure Liquid methods, Isomerism, Magnetic Resonance Spectroscopy, Phosphates chemistry, Phosphoadenosine Phosphosulfate metabolism, Phosphotransferases chemistry, Carrier Proteins chemistry, Chromatography, Affinity methods, Phosphoadenosine Phosphosulfate analogs & derivatives, Phosphotransferases isolation & purification, Phosphotransferases (Alcohol Group Acceptor)
- Abstract
3'-Phosphoadenosine 5'-phosphosulfate (PAPS) functions as the high-energy sulfate donor for sulfate ester synthesis in all higher organisms. This activated sulfate, like its adenosine 5'-phosphosulfate precursor, is both chemically labile and vulnerable to sulfohydrolase degradation. These obstacles have limited the utility of the native PAPS in the purification and mechanistic description of the numerous PAPS-utilizing enzymes. This paper describes the synthesis of the 2'- and 3'-isomers of a nonhydrolysable, and thus stable, PAPS analog, beta-methylene-PAPS, from the previously described beta-methylene-APS (L. Callahan et al., Anal. Biochem. 177, 67-71, 1989). The method involves phosphorylation of beta-methylene-APS with trimetaphosphate and separation of the resulting mixed 2'(3')-isomers by ion-pair reverse-phase HPLC. The utilization of this analog as an inhibitor of APS kinase and PAPS translocase, two of the numerous PAPS-utilizing activities, as well as an affinity ligand for purification of APS kinase, is described.
- Published
- 1991
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22. Spectrophotometric determination of iron and cobalt with Ferrozine and dithizone.
- Author
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Dawson MV and Lyle SJ
- Abstract
Procedures are described whereby iron (1-50 microg) and cobalt (1-25 microg) are determined spectrophotometrically, iron as iron(II) with the disodium salt of 3-(2-pyridyl)-5,6-bis(4-phenylsulfonic acid)-1,2,4-triazine (Ferrozine) and cobalt as the cobalt(III) dithizonate complex. The reduction to iron(II) prevents interference of iron(III) in the cobalt determination, and both metals can be determined in the same portion of sample solution. Removal of interference by other metal ions is described.
- Published
- 1990
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23. Incidence and treatment of abnormal postpartum ovarian function in dairy cows.
- Author
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Archbald LF, Norman SN, Bliss EL, Tran T, Lyle S, Thomas PG, and Rathwell AC
- Abstract
The objectives of this study were to determine 1) the incidence of abnormal postpartum ovarian function in a large dairy herd in North Central Florida and 2) the effectiveness of gonadotrophin releasing hormone (GnRH) in treating this condition. The study was conducted from April 1988 to June 1989. The internal genitalia of the cows were initially examined per rectum (Day 0) between 19 and 29 (23 +/- 0.25) d after calving and again 14 d later (Day 14) for evidence of uterine involution and ovarian activity. The presence of a palpable corpus luteum (CL) and retrospective determination of plasma progesterone (P4) concentrations > 1 ng/ml were the criteria used to assess ovarian activity. Cows possessing a palpable CL and P4 concentrations > 1 ng/ml on Day 0 were determined to be cycling normally. A total of 1356 cows was used in this study. On Day 0, two groups were formed: Group 1 consisted of normal, cyclic cows, Group 2 of noncyclic cows. On Day 0, alternate cows in Group 2 were treated with GnRH (100 microg i.m). On Day 14, the previously nontreated cows in Group 2 were further divided into two groups, forming Group 3, nontreated cows and Group 4, cows treated with GnRH at this time. Group 5 was comprised of cows from Group 2 that did not respond to treatment with GnRH on Day 0; these cows were treated on Day 14 with GnRH (100 microg i.m). Group 6 was comprised of nontreated cows from Group 2 that responded spontaneously (presence of a CL) by Day 14. Reproductive parameters evaluated were the percentage of cows pregnant within 180 d after calving and at the end of the study, the number of days open and the number of services per conception. Data were statistically analyzed using Chi square and survival analysis. The results of this study indicate that the incidence of abnormal postpartum ovarian function in this herd was 30.2% and that the nontreated cows experienced more days open and required more services per conception than the treated cows, those that were cycling normally on the initial examination, and those that responded spontaneously by Day 14.
- Published
- 1990
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24. Extraction and spectrophotometric determination of cobalt with dithizone.
- Author
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Dawson MV and Lyle SJ
- Abstract
Cobalt(II) in acetate-tartrate buffer (pH 6.0-7.3) is extracted quantitatively as cobalt(III) dithizonate with excess of dithizone in CCl(4). The molar absorptivity in the CCl(4) phase is 4.6 x 10(4) 1.mole(-1).cm(-1) at the absorption maximum 550 nm. The calibration graph is linear for 1-10 mug of cobalt in 10 ml of CCl(4) when excess of dithizone is removed by back-extraction with 0.01M aqueous ammonia. Most interferences can be overcome by (a) initial extraction with dithizone at pH 1.3, (b) selective back-extraction into hydrochloric acid (pH 1 to 2), (c) oxidation of iron and tin to iron(III) and tin(IV) and addition of fluoride to complex the former, and (d) selective reaction of nickel dithizonate with 1,10-phenanthroline in the CCl(4) phase followed by back-extraction of nickel into 0.1M acid. The method has been applied to determination of cobalt in a copper-nickel-zinc alloy and a nimonic alloy.
- Published
- 1990
- Full Text
- View/download PDF
25. Observations on a dropping-mercury electrochemical detector for flow-injection analysis and HPLC.
- Author
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Lyle SJ and Saleh MI
- Abstract
An electrochemical detector cell having a dropping-mercury working electrode and an Ag/ AgCl reference electrode is examined with reference to applications in flow-injection analysis and high-performance liquid chromatography. The working electrode, fed by a horizontal capillary, is capable of delivering mercury at fast dropping rates which can be varied by a control device in the cell. Examples of application to inorganic and organic electroreducible species are considered and advantages and limitations relative to other electrochemical detector devices are discussed.
- Published
- 1981
- Full Text
- View/download PDF
26. A spectrophotometric determination of europium in lanthanide and other mixtures by use of Methylene Blue.
- Author
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Bhattacharya S, Lyle SJ, and Maghzian R
- Abstract
A spectrophotometric determination of 0.1-1 mg of europium in a lanthanide(III) mixture is described. Europium(III) is selectively reduced in a Jones reductor and the europium(II) allowed to react with a measured excess of Methylene Blue (MB) solution. The dye is reduced to the colourless leuco form according to the equation, MB + 2 Eu(II)-->leuco MB + 2 Eu(III) and the excess of MB is determined spectrophotometrically at 664 nm. Optimum conditions are discussed and various applications presented.
- Published
- 1980
- Full Text
- View/download PDF
27. Radioisotope studies of carboxyl sites on strong acid and strong base ion-exchange resins derived from polystyrene.
- Author
-
Armitage GM, Lyle SJ, and Nair VC
- Abstract
The pH-dependent distribution of carrier-free radioisotopes between aqueous phases at constant ionic strength and polystyrene-divinylbenzene type exchangers reveals the presence of a secondary exchange function attributable to carboxyl groups. Cation- and anion-exchangers of the sulphonate and quaternary ammonium types possess this additional cation-exchange capacity which is, however, relatively very low in currently available commercial resins. Its influence on separations involving radioisotopes of high specific activity is discussed.
- Published
- 1976
- Full Text
- View/download PDF
28. An exploratory study of the indirect fluorimetric determination of uranium(VI) by energy transfer and measurement of fluorescent emission by europium(III).
- Author
-
Lyle SJ and Za'tar NA
- Abstract
A fluorimetric determination of uranium(VI) is described. It is based on the emission from europium(III) at 594 nm, following its indirect excitation by uranium.
- Published
- 1986
- Full Text
- View/download PDF
29. Some ion-exchange resins for anion-chromatography.
- Author
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Al-Omair AS and Lyle SJ
- Abstract
The quaternary ammonium salts, n-butyltrimethylammonium iodide, 1,1,3,3-tetramethylbutyltrimethylammonium iodide, n-octadecyltrimethylammonium iodide and tri-n-dodecylmethylammonium iodide were synthesized from commercially available amines and together with n-hexadecyltrimethylammonium bromide tested for retention by a series of macroreticular resins (XAD-2, XAD-4, XAD-7, XAD-8 and XAD-11) for use as "surface" ion-exchangers in the chromatography of anions. Exchange-capacity studies of the coated resins showed that the non-polar XAD-2 and XAD-4 resins had retention characteristics superior to those of the polar resins and that pore size in the resin was more important than surface area per unit weight of resin. Tri-n-dodecylmethylammonium salts in XAD-2 gave the highest exchange capacity, with best retention under elution conditions. Columns prepared from this anion-exchanger were used to separate and analyse simple mixtures of anions (chloride, nitrate and sulphate) each within the 1-30 ppm range, by single-column operation with indirect photometric detection and also by conductivity detection with background-ion suppression. Though of use for the determination of anions in simple mixtures, the resolution and performance were generally poorer than those displayed by a commercial (Dionex) column. This is at least partly attributable to the inferior column-packing properties of the granular XAD-resin.
- Published
- 1987
- Full Text
- View/download PDF
30. Reversed-phase partition chromatographic separations with 2-ethylhexyl dihydrogen phosphate and di-2-ethylhexyl hydrogen phosphate.
- Author
-
Lyle SJ and Nair VC
- Abstract
Di-2-ethylhexyl hydrogen phosphate (HDEHP) and 2-ethylhexyl dihydrogen phosphate (H(2)MEHP) are compared as stationary phases in reversed-phase chromatography of selected lanthanides, strontium, yttrium, barium, manganese(II), iron(III), cobalt(II), nickel, gold(III), platinum(IV), palladium(II) and silver. Chromatograms were mainly developed with hydrochloric acid at various concentrations. In general H(2)MEHP was found to be less satisfactory than HDEHP. Development of chromatograms by dilute aqueous electrolytes on paper is slower and separations of chemically similar metals such as lanthanides is not encouraging. However, movement of lanthanides by EDTA at pH 3 in an aqueous sodium perchlorate medium occurs only on H(2)MEHP-treated paper. Good separations of iron(III) and cobalt(II) are possible on paper treated with either ester, and gold(III) and platinum(IV) are separated on HDEHP-impregnated paper. Column methods for the separation of carrier-free gold-199 and iron-59 from macro-amounts of neutron-irradiated platinum and cobalt, respectively, have been developed.
- Published
- 1969
- Full Text
- View/download PDF
31. Co-precipitation of metal dimethylglyoximates generated from biacetyl monoxime or biacetyl and hydroxylamine.
- Author
-
Lyle SJ and Maghzian R
- Abstract
A study has been made of some aspects of the co-precipitation of gold and platinum(II) and (IV) with palladium(II) precipitated from homogeneous solution initially containing biacetyl and hydroxylamine in 0.3M hydrochloric acid. The co-precipitation of nickel(II) with palladium(II) and vice versa from near neutral solutions initially containing biacetyl and hydroxylamine was also explored; the solid is enriched in the minor constituent in both cases. As with biacetyl monoxime-hydroxylamine systems, both nickel(II) and palladium(II) promote formation of dimethylglyoxime from such solutions between pH 7 and 8. Factors leading to this unusual behaviour in co-precipitation are discussed and a qualitative explanation tentatively advanced. The co-precipitation of nickel and palladium(II) is different when biacetyl monoxime solutions are used; the former comes out of solution faster than the latter irrespective of their concentration ratio. This disparity in the reaction rates can be used to separate nickel directly from palladium(II) by precipitation or extraction of the dimethylglyoximate into chloroform.
- Published
- 1969
- Full Text
- View/download PDF
32. Precipitation of nickel dimethylglyoximate.
- Author
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Lyle SJ and Maghzian R
- Abstract
The homogeneous precipitation method of Salesin and Gordon and the aqueous acetone precipitation described by Jones and Howick are examined for the determination of nickel as the dimethylglyoximate and where applicable comparisons are made with a direct (conventional) precipitation of this substance. The co-predpitation of iron and cobalt was studied radiometrically under various experimental conditions. Relevant solubility data are also presented. Application of the methods to the determination of nickel in alloy steels showed that in the absence of cobalt there is little to choose between them. For cobalt steels the method of Jones and Howick is more convenient than that of Salesin and Gordon and more satisfactory than a conventional precipitation and gravimetric finish.
- Published
- 1967
- Full Text
- View/download PDF
33. Separation of carrier-free silver from neutron-irradiated palladium.
- Author
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Lyle SJ and Maghzian R
- Abstract
The use of a chelate-forming ion-exchange resin for the separation of carrier-free silver-111 from neutron irradiated palladium is described. On décrit l'emploi d'une résine échangeuse d'ions formant des chélates pour la séparation de l'argent-111 exempt d'entraîneur du palladium irradié aux neutrons.
- Published
- 1968
- Full Text
- View/download PDF
34. A separation of protactinium from neutron-irradiated thorium.
- Author
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Lyle SJ and Shendrikar AD
- Abstract
A convenient-method, based on liquid-liquid extraction with N-benzoyl-N-phenylhydroxylamine in chloroform, is given for the separation of protactinium-233 from neutron-irradiated thorium.
- Published
- 1966
- Full Text
- View/download PDF
35. Mass spectrometric study of the deterioration of polystyrene-based ion-exchangers.
- Author
-
Armitage GM and Lyle SJ
- Abstract
A mass spectrometric study of the aging effects in polystyrene-based ion-exchangers has been made. Fragments in the m/e range 10-70 were examined and attributed to OH(+), H(2)O(+), CO(+), CO(+)(2), supplemented by SO(+) and SO(+)(2) from sulphonic-acid cation-exchangers. Ion-current intensities were found to be dependent on the state of the resin.
- Published
- 1973
- Full Text
- View/download PDF
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